Martin
ASM-N-7/GAM-83/AGM-12Bullpup

The Bullpup was the first successful guided
tactical air-to-ground missile of the U.S. Navy and the USAF. Although it had
severe limitations, it was produced in very large numbers.

Development of the Bullpup was initiated by the
U.S. Navy in 1953, when an operational requirement was issued for a
short-range air-to-ground guided missile. The two primary goals were to give
the ground-attack aircraft a standoff missile to avoid prolonged exposure to
enemy ground fire, and to increase the chances of destroying targets which are
hard to hit with free-fall bombs (like e.g. bridges). The design competition
was won by Martin, and in April 1954, the company received the contract to
develop and produce the new missile, designated ASM-N-7 Bullpup. It was
a relatively small missile with a 113 kg (250 lb) warhead, which was optically
tracked and manually guided by the pilot. The first successful air launch of
an XASM-N-7 prototype occurred in June 1955, followed by YASM-N-7 evaluation
models. In April 1959, the ASM-N-7 Bullpup production version entered
U.S. Navy fleet service. The majority of the production missiles was built by
Maxson Electronics.

The ASM-N-7 was a roll-stabilized missile, powered by an
Aerojet MK 8 solid-fuel rocket motor, and with a simple derivative of a
standard 113 kg (250 lb) bomb as warhead. After visual identification of the
target, the pilot launched the missile, and used two small flares at the back
of the missile to track its flight path. Using a small control stick to
transmit radio commands to the Bullpup, he manually guided the missile
to its target. This system was extremely simple, and therefore the Bullpup
could be used with almost every aircraft, even including Sikorsky HUS-1
(UH-34D) helicopters. Of course, this simple manual guidance principle also
had severe drawbacks, the main one being that the aircraft, the missile, and
the target essentially had to remain in a straight line during guidance,
making the aircraft vulnerable to ground fire (and thereby somewhat negating
one of the original reasons for using missiles instead of bombs). The radio
command equipment in the launching aircraft was usually an AN/ARW-73 or
AN/ARW-77 system. There was also a completely inert handling practice variant
of the ASM-N-7, designated as TASM-N-7.

After tests with YASM-N-7a missiles, the improved
ASM-N-7a Bullpup A was introduced in 1960. It replaced the solid-fuel
motor with a Thiokol (Reaction Motors) LR58-RM-4 liquid-fueled rocket engine
with storable propellants, increasing the range of the missile. The 113 kg
(250 lb) warhead was also improved.

Click on Picture to enlarge

ASM-N-7a (AGM-12B)

The ASM-N-7b Bullpup B was a significantly
enlarged version. It had a 453 kg (1000 lb) warhead in a larger body section,
enlarged wings, and a new Thiokol LR62-RM-2/4 rocket engine of much higher
thrust. It was first tested in 1962, and became operational in 1964. The new
motor gave the ASM-N-7b a still larger dynamic range, but because of the
visual guidance system, effective range remained essentially the same. The
Bullpup B was eventually also used by the USAF.

Click on Picture to enlarge

Foreground: ASM-N-7b (AGM-12C)
Background: GAM-83A (AGM-12B)

U.S. Air Force involvement in Bullpup development
began around 1955, when the USAF contracted Martin to develop an advanced
derivative of Bullpup, designated GAM-79 White Lance. It was to
use a Thiokol LR44-RM-2 storable liquid-fuel rocket engine, and was to have a
nuclear warhead option. Another new feature of the GAM-79 was an improved
radio command guidance, which no longer required the aircraft, missile and
target to be permanently in line during guided flight. This allowed the pilot
to fly evasive maneuvers with his aircraft and the missile. Because the
development of the White Lance would need some time, the USAF decided
to procure the unmodified ASM-N-7 Bullpup as an interim missile, with
the designation GAM-83.

The GAM-79 White Lance missile was gradually
merged into ongoing Bullpup development, and the result was a missile,
which was essentially the same as the U.S. Navy's ASM-N-7a Bullpup A,
with the exception of the improved guidance system. The GAM-79 designation and
White Lance name were therefore dropped, and the missile became the
GAM-83A Bullpup. The GAM-83B was a derivative of the GAM-83A with a
body section of slightly larger diameter, which could optionally be fitted
with a 1-15 kT W-45 nuclear fission warhead. For Bullpup training,
Martin developed a modified 12.7 cm (5 in) rocket with tracking flares and
radio command receiver. This rocket was designated as TGAM-83 by the USAF.

In June 1963, all Bullpup missiles were
re-designated in the AGM-12 series, as follows:

Old Designation

New Designation

TGAM-83

ATM-12

ASM-N-7
GAM-83

AGM-12A

ASM-N-7a
GAM-83A

AGM-12B

ASM-N-7b

AGM-12C

GAM-83B

AGM-12D

The re-designation included two irregularities. First,
the use of the AGM-12B designator for two non-identical Navy and USAF versions
was at least confusing. Second, the assignment of the plain ATM-12 designator
without a suffix letter was against the rules which required suffixes for all
versions. Some AGM-12A/B/D missiles were later converted to inert training
rounds and designated ATM-12A/B/D.

Click on Picture to enlarge

From front: ATM-12, AGM-12D, AGM-12B, AGM-12C

The final production Bullpup version was the
USAF's AGM-12E. This variant was a derivative of the AGM-12C, in which the
unitary warhead was replaced by an anti-personnel cluster bomb warhead. The
AGM-12E was intended for use against anti-aircraft sites in Vietnam, but was
produced in very limited numbers only.

The AGM-12 was used by both the U.S. Navy and the USAF in
Vietnam, but because of the missile's inherent limitations, it's not
surprising that the overall results were disappointing. However, because of
the large numbers built until production ceased in 1969, the AGM-12 remained
in U.S. service for some time, and while phase-out began in the mid-1970s, the
last AGM-12Cs were not retired until the early 1980s. In total, more than
30000 Bullpup missiles of all versions have been built, most of these
as AGM-12A/B (only about 4600 AGM-12C and 800 AGM-12E are included in the
total). The majority of the production missiles were built by Maxson
Electronics under subcontract from Martin Marietta. Maxson is also attributed
with a version designated AEM-12F. I have no firm details about this variant,
but there are indications that it was a missile which had jamming equipment
instead of a warhead.

There were several projects which sought to improve the
Bullpup by replacing the manual guidance by some sort of autonomous
guidance system. These efforts resulted in the experimental derivatives AGM-79 Blue
Eye,
AGM-80 Viper, and AGM-83 Bulldog.

Specifications

Note: Data given by several sources show slight
variations. Figures given below may therefore be inaccurate!

The AGM-12 Bullpup command-guided missile was the first
mass-produced air-to-surface guided missile. The disappointing Korean
bridge-bombing experience stimulated the Navy to pursue development of the
postwar Bullpup program.

The ASM-N-7 Bullpup was first deployed overseas in April
1959 when VA-212, equipped with FJ-4B Furies, sailed from Alameda on board
Lexington to join the Seventh Fleet in the western Pacific. The following
August, VA-34, equipped with A4Ds sailed from the east coast abroad the
Saratoga to join the Sixth Fleet, thus extending Bullpup deployment to the
Mediterranean.

The original ASM-N-7 Bullpup was soon upgraded to an
improved variant, the ASM-N-7A, in 1960, which was redesignated AGM-12B
Bullpup-A in 1962. The AGM-12B was put into second source production by W.L.
Maxson. Production terminated in 1970 at 22,100 rounds.

The AGM-12C Bullpup B was a larger follow-on version of
the original Bullpup air-to-surface radio-guided missile. The AGM-12C carried
a 1,000 pound semi-armor-piercing warhead in the enlarged midsection. The
largest of the Bullpup series of missiles, the AGM-12C is also the
oddest-looking member, distinguished from the other Bullpup versions by its
unusual long-chord wings. It weighed 1,785 pounds and used a 30,000-pound
thrust liquid-fuel rocket engine to achieve a range of ten miles. The pilot
guided the missile by watching the position of tail-mounted tracking flares in
relation to his line-of-sight view of the target. Steering commands to correct
the missile flight path were sent via one of the 24 available radio channels.

The Bullpup B entered USAF service in 1965, and was
carried by F-4 and F-105 fighters during the Vietnam war. Its small warhead,
however, was totally inadequate against North Vietnamese bridges. The Navy's
Walleye proved better.

The AGM-12D was a nuclear variant originally known as the
GAM-83B, but redesignated the AGM-12D. This variant looked much like the
AGM-12B, but had a slightly larger diameter that allowed it to carry either a
conventional or tactical nuclear warhead.

The AGM-12E had a cluster bomb warhead intended for use
against anti-aircraft sites, but only about 840 were built.

More than 4,600 AGM-12Cs and 800 AGM-12Es were built.
They were withdrawn from USAF service in the mid-1970s. Foreign users included
the Royal Navy and various NATO forces. Some Bullpups are still in service,
usually in ground attack training programs.

AGM-83 Bulldog was a laser-guided version of Bullpup that
was never produced.